Method for salvaging carbon from anodes

ABSTRACT

Carbon anode blocks are separated from metallic suspending devices of used or defective anode units for the production of aluminum by clamping the suspending device between one or more pairs of piston rods, by stripping the anode block off the thus clamped suspending device, and by thereupon comminuting the separated anode block in a crushing chamber which is surrounded by toothed walls at least one of which is movable into the chamber to thus comminute the anode block. An overhead conveyor is employed to transport used or defective anode units into the range of the clamping faces on the piston rods. The crushing chamber is located below the separating station so that a separated anode block can enter the crushing chamber by gravity.

United States Patent Limpinsel et al.

[ 51 Apr. 25, 1972 METHOD FOR SALVAGING CARBON FROM ANODES lnv nm Gunter Limpinsel, Forsbach/Bezirk Cologne, Germany; Karl Fricker, Meilen. Switzerland Assignees: Kuhn Hartung & Co. Maschineni'abrik GmbH; Duesseldorf, Germany; Schweizerische Aluminium AG, Zurich, Switzerland Filed: May 21, 1969 Appl. No.: 826,476

Foreign Application Priority Data Sept. 19,1968 Germany .l ..P 17 83 018.1

US. Cl ..24l/25, 241/29 Int. Cl. ..B02c 1/06, B02C 23/00 Field ofSearch ..24l/25,27, 29, 30, 101,152,

[56] References Cited UNITED STATES PATENTS 2,208,165 7/1940 Sheahan ..24l/D1G. 22

FOREIGN PATENTS OR APPLlCATlONS 705,030 4/1941 Germany ..241/D1G. 22

'Niemann ..15/104.04

Primary Examiner-Donald G. Kelly Attorney-Michael S. Striker [57] ABSTRACT Carbon anode blocks are separated from metallic suspending devices of used or defective anode units for the production of aluminum by clamping the suspending device between one or more pairs of piston rods, by stripping the anode block offthe thus clamped suspending device, and by thereupon comminuting the separated anode block in a crushing chamber which is surrounded by toothed walls at least one of which is movable into the chamber to thus comminute the anode block. An overhead conveyor is employed to transport used or defective anode units into the range of the clamping faces on the piston rods. The crushing chamber is located below the separating station so that a separated anode block can enter the crushing chamber by gravity.

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PATENTEDAPRZS I972 3.658.261 sum 30F 4 INVENTORSI:

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METHOD FOR SALVAGING CARBON FROM ANODES BACKGROUND OF THE INVENTION The present invention relates to an improved method for recovering carbon from anodes, particularly for salvaging carbon from remnants of anode units or from defective anode units of the type used in the production of aluminum. Still more particularly, the invention relates to a method for automatic or semiautomatic salvaging and further processing of anode carbon.

It is already known to salvage carbon from anode units. Such anode units normally comprise a metallic suspending device for a carbon block. The remnants of used anode blocks and/or blocks of defective anode units are salvaged by imparting to the anode block one or more blows to thus fragmentize the carbon block and effect separation of resulting fragments from the suspending device. A drawback of such procedure is that the suspending device is likely to be damaged, that the fragmentizing of anode blocks cannot be controlled, that it is difficult to intercept and collect fragments of anode blocks, and that fragments of carbon often adhere to suspending devices so that each suspending device must be inspected and/or cleaned in a subsequent time-consuming operation. The problem is even more acute when the material which is used to anchor the suspending device in the anode block is a metal; such material cannot be properly segregated from the so-called spade or spades of the suspending device by impacts against the anode block. As a rule, the just described conventional apparatus are too slow for efficient and economical salvaging of carbon and suspending devices.

It is also known to salvage anode carbon in so-called impact crushers; however, the fragmentizing action of such crushers is unsatisfactory so that the fragmentized blocks of carbon must be subjected to further comminuting treatment. Furthermore, the wear on the components of impact crushers is very pronounced; this results in high maintenance and operating costs.

SUMMARY OF THE INVENTION.

An object of our invention is to provide a method according to which the anode blocks can be separated from suspending devices of used or defective anode units in a novel and improved way, and according to which the thus separated blocks can be comminuted to a desired size which is best suited for the production of fresh anode blocks.

Another object of the invention is to provide a method according to which segregation of suspending devices from anode carbon blocks takes place simultaneously with treatment of suspending devices, and according to which the comminution of separated anode blocks can take place in immediate or close proximity of the separating station so that the blocks need not be transported to the comminuting station.

A further object of the invention is to provide a novel method of cleaning separated suspending devices of anode units.

Still another object of the invention is to provide an apparatus which can be resorted to in the practice of the above outlined method, wherein the suspending devices of anode units are treated gently, and which can be operated either intermittently or continuously to effect separation of anode carbon from batches of anode units or from continuously delivered anode units.

An ancillary object of the invention is to provide the apparatus with novel separating and comminuting instrumentalities.

An additional object of the invention is to provide a novel conveyor system for delivery of anode units to the separating station.

A further object of the invention is to provide an apparatus which can treat different types of anode units and which can anode units.

The method of our invention is utilized for salvaging or recovering carbon from anode units of the type wherein a first portion including a carbon anode block is connected with a second portion including a suspending device which consists, at least in part, of metallic material. The method comprises the steps of holding one portion of a used or damaged anode unit against movement with the other portion, moving the other portion with reference to the one portion to thus separate the anode block from the suspending device, and thereupon subjecting the separated anode block to a comminuting operation. The last mentioned step preferably comprises converting the anode block into a mass of granulae by subjecting it to a series of crushing actions. It is often desired to level or rake the granular material in the course of the comminuting operation which is preferably performed in the chamber of a housing one or more walls of which are provided with teeth and at least one wall of which is movable into the chamber to thus subject anode blocks to a rapid, efficient and predictable comminuting action.

The step of holding one portion of the anode unit against movement with the other portion preferably comprises mechanically clamping the suspending device, and the step of moving the other portion with reference to the one portion then comprises mechanically separating the anode block from the thus clamped suspending device, preferably by pushing the anode block away from the clamped suspending device by one or more stripping elements which can be moved by hydraulic or pneumatic cylinder and piston assemblies.

In accordance with another feature of our method, the exterior of the suspending device is cleaned, preferably in the course of separation of an anode block from the suspending device, by scraping a portion of the suspending device.

If the anode blocks are relatively small, or if the apparatus is equipped with a relatively large comminuting assembly, two or more anode blocks can be separated from the suspending devices of successively delivered anode units and the thus separated anode blocks are thereupon comminuted in a simultaneous operation.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The apparatus for carrying out the method itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of an apparatus which embodies the invention, an anode unit being shown during transport toward the separating station;

FIG. 2 is a view of the anode unit as seen in the direction of arrow II in FIG. 1, with a portion of the anode block broken away;

FIG. 3 is an enlarged view of a detail of the apparatus shown in FIG. 1;

FIG. 4 is a plan view of the apparatus with the conveyor for anode units omitted, the operative positions of certain parts of the apparatus being indicated by phantom lines;

FIG. 5 is a fragmentary sectional view as seen in the direction of arrows from the line V-V of FIG. 3;

FIG. 6 is an enlarged fragmentary vertical sectional view of the comminuting assembly, substantially as seen in the direction of arrows from the line VI-VI of FIG. 4;

FIG. 7 is a fragmentary horizontal sectional view as seen in the direction of arrows from the line VII-VII of FIG. 6;

FIG. 8 is a smaller-scale view as seen in the direction of arrow VIII in FIG. 6 but turned in the plane of the drawing through and FIG. 9 is a similar smaller-scale view as seen in the directio of arrow IX of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 2, there is shown a so-called anode unit 1 which contains a prebaked carbon anode block 2 and a suspending device which supports the block 2 and mounts it in an aluminum producing cell. The block 2 is a remnant whose material should be salvaged upon withdrawal from the cell. The suspending device includes an anode rod 3 which is made of aluminum or other suitable current-conducting metal and carries at its lower end a so-called anode spade 4 consisting of steel or another metal with a high melting point. The spade 4 is bifurcated and its prongs 4a are fitted into recesses or bores provided therefor in the head of the anode block 2. These prongs 4a are surrounded by a plastic mass 5 which is tamped into the bores and consists of carbon. It is also known to employ a metallic anchoring means which is poured into the bores around the prongs of the spade. The exposed upper portions of the prongs 4a are surrounded by collars 6 consisting of carbon and serving to protect the spade against the influence of molten bath in the electrolytic furnace. The upper end portion 7 of the anode rod 3 is forked and carries a transversely extending pin 8 on which the suspending device is mounted in a furnace.

The apparatus serves for separating the suspending device from the anode block 2 and for comminuting the block subsequent to separation. The apparatus comprises basically a separating assembly 9 which separates blocks 2 from their suspending devices and a crushing or comminuting assembly 10 which thereupon reduces the blocks to fragments. The comminuting assembly 10 is located at a level below the separating assembly 9. This crushing assembly 10 supports two frame members or beams 21 (see FIGS. 1 and 4) each of which supports a guide frame or ways 45 in such a way that the guide frames are movable at right angles to the direction of transport of anode units 1. The guide frames 45 support the parts of the separating assembly 9 and their adjustability in a direction at right angles to the direction of travel of anode units 1 enables the assembly 9 to assume an optimum position with reference to differently dimensioned and/or configurated anode units. Cylinders 46 mounted on the guide frames 45 serve as a means for moving carriages 47 for two clamping or holding devices ofthe separating assembly 9. The cylinders 46 have piston rods which can move the clamping devices in directions at right angles to the direction of travel of anode units 1. The clamping devices are best shown in FIG. 3. Each thereof comprises two horizontal supports or guides 11a for clamping or holding cylinders 11. The cylinders 11 of each clamping device are in axial alignment with each other (see FIG. 4). These cylinders have piston rods 12 which are movable toward and away from each other by a gaseous or hydraulic pressure medium. The inner ends of the piston rods 12 are provided with clamping or holding faces 13 which can engage an anode spade 4 from opposite sides (see FIG. 3) on which a carbon block 2 is suspended.

The block moving or stripping device of the separating assembly 9 comprises pairs of vertical stripping or moving cylinders 14 mounted on supports or guides 14a and having piston rods 18. The lower ends of the piston rods 18 are provided with stripping or moving elements 19. The cylinders 14, their supports 14a and piston rods 18 are movable toward and away from each other in synchronism with the piston rods 12 of the clamping cylinders 11. For the sake of simplicity, the supports 14a are mounted directly on the piston rods 12 so that the cylinders 14 necessarily share all horizontal reciprocatory movements of the piston rods 12 with reference to the clamping cylinders 11 and supports 11a. In order to hold the cylinders 14 against tilting, each support 14a is provided with a post 17 which is slidable in a bearing sleeve 16 provided at the upper end of an arm secured to the respective support 110. The posts 17 are parallel to the piston rods 12.

The aforementioned stripping or moving elements 19 at the lower ends of piston rods 18 are provided with cleaning members or scrapers 20 (FIG. 3) serving as a means for cleaning the exposed surfaces of spades 4. The length of scrapers 20 (as considered in the axial direction of piston rods 18) can be less than the axial length of stripping elements 19. Also, the width of scrapers 20 can be less than the diameter of a stripping element 19. As a rule, the dimensions of elements 19 and scrapers 20 will depend on the sizes of the blocks 2 and on the dimensions of spades 4.

FIG. 4 shows that the apparatus comprises two pairs of clamping cylinders 11, two pairs of stripping cylinders 14 and hence two pairs of stripping elements 19 and two pairs of scrapers 20. However, if the anode units are rather small, the apparatus can comprise a single pair of cylinders 11, a single pair of cylinders 14 and only one pair of elements 19 and one pair of scrapers 20. Two pairs of such parts are of advantage when the anode blocks 2 are large.

The conveyor means for transporting successive anode units 1 into the range of the clamping or holding faces 13 in the separating assembly 9 comprises an overhead rail 25 for trolleys 22 each of which supports the pin 8 of a suspending device in an anode unit. Each trolley 22 comprises a frame 23 with front and rear wheels 24 which travel along the rail 25. Each frame 23 is formed with a hook 26 which engages the pin 8 of the corresponding anode unit 1. A mechanical blocking device 27 (shown in FIGS. 3 and 5) is provided to maintain anode rods 3 in optimum positions for separation of blocks 2. The blocking device 27 comprises two parallel carriers or rails 28 flanking the path of movement of successive anode rods 3 below the rail 25. The width of the passage or channel defined by the rails 28 exceeds somewhat the width of an anode rod 3. Each rail 28 supports a pivotable jaw 29 which is biased by a helical spring 48 so that it normally abuts against a stop shoulder 280 on the corresponding rail 28. The jaws 29 have inclined cam faces 52 which extend into the channel between the rails 28 and can be engaged by an anode rod 3 which is advanced by its trolley 22 in the direction indicated by arrow 28A. When the rod 3 engages the cam faces 52, the jaws 29 pivot in directions to stress the respective springs 48 and to permit passage of the rod 3. The springs 48 thereupon contract and return the jaws 29 into abutment with the corresponding stops 28a. The pallets of the jaws then prevent movement of the rod 3 counter to the direction indicated by arrow 28A. The vertical pivots for the jaws 29 are shown at 50. The edge faces of teeth on the jaws 29 are shown at 51. When the jaws 29 abut against the stops 28a, the cam faces 52 make with each other an angle of less than preferably an acute angle. The edge faces 51 prevent swinging of anode rods 3 when the corresponding trolleys 22 come to a halt; they extend transversely across the channel between the rails 28 when thejaws 29 abut against the stops 28a.

The clamping or holding faces 13 on the piston rods 12 can be readily designed to properly engage and hold anode spades whose prongs 4a are of other than polygonal outline, for example, to clamp round, square, rectangular or otherwise configurated prongs.

The details of the comminuting assembly 10 are shown in FIGS. 1, 4 and 6 to 9. This assembly comprises a housing defining a crushing chamber 30 having an inlet 300 located at a level below an anode unit 1 which is suspended on the rail 25 and is engaged by the blocking device 27. The housing of the comminuting assembly 10 comprises a stationary upright crushing wall 31 and a second upright crushing wall 32 which is parallel with and is movable toward the away from the wall 31 (see FIGS. 1, 4 and 6). The means for moving the wall 32 comprises a hydraulic double-acting cylinder 33. The inner sides of the walls 31, 32 are provided with crushing projections or teeth of different size and/or shape. The short teeth are shown at 34 and the longer teeth are denoted by numerals 35, 35a, 36 and 37. The teeth 34 have sharp tips; the teeth 37 have horizontally extending cutting edges; and the cutting edges of teeth 35, 35a and 36 are vertical. However, it is equally within the purview of our invention to utilize pyramidal or conical teeth 35, 35a, 36 and/or 37 each of which is formed with a sharp tip.

The teeth on the wall 31 are staggered with reference to teeth on the wall 32. The feature that the cutting edges of some teeth are horizontal and that the edges of certain teeth are vertical, combined with the aforementioned staggering of teeth, insures a very satisfactory comminuting action in the crushing chamber 30. The upper and lower portions of the fixed wall 31 are provided with five aligned teeth each, and the teeth 35 of the upper portion are in vertical alignment with teeth 35 of the lower portion. This is clearly shown in FIG. 8 which shows the wall 31 in a position turned through an angle of 90 in the plane of the drawing. Thus, the two rows of teeth 35 (five teeth per row) are horizontal, not vertical. The teeth 35 of each row are preferably but need not be equidistant from each other. Two pairs of vertically aligned teeth 35a are provided in the median portion of the wall 31 with each pair adjacent to one of its lateral sides. The two pairs of teeth 35a flank a horizontal distributing or leveling ram 38 which constitutes a movable central portion of the wall 31. A double- ;acting hydraulic cylinder 39 serves as a means for reciprocating the ram 38. The central portion of the ram 38 is provided with a pair of vertically aligned teeth 36. The aforementioned pairs of teeth 350 are closely adjacent to the short vertical sides of the ram 38. Each tooth 36 is located in a common horizontal plane with two teeth 35a. The teeth 36 are located in the plane of the centrally located pair of teeth 35. As stated before, the edges of the teeth 35, 35a and 36 are vertical.

t The teeth 37 on the movable wall 32 form two horizontal rows of four teeth each. The teeth 37 of each row are equidistant from each other and each tooth 37 of the upper row isaligned with a tooth 37 of the lower row- The cutting V e'dges of teeth 37 are horizontal. The upper row of teeth 37 is located in a horizontal plane extending between the upper row of teeth 35 and the adjoining teeth 35a, 36. The lower row of I teeth 37 is located in a second horizontal plane which extends I between the lower row of teeth 35 and the adjoining lower teeth 35a, 36. Furthermore, the teeth 37 are offset in horizon- 1 tal direction with reference to the teeth 35, 35a, 36 on the wall 3%}. The shorter teeth 34 on the walls 31, 32 are of identical configuration; however, the tips of teeth 34 on the wall 31 are aligned with the recesses between the roots of teeth 34 on the wall32, and vice versa. The foremost or innermost position of the wall 32 is shown in FIG. 7 by phantom lines.

The bottom wall 40 of the housing which defines the crushing'chamber 30 and includes the walls 31, 32 constitutes a "gate or closure which is pivotally mounted in the housing and f. j isturnable about a horizontal pintle 40a (FIG. 1) by means of q a link 41 which is coupled to the piston rod of a double-acting vcylinder 42. The latter is articulately connected to the housing, as at 42a. A locking member 43 is provided on the housing of the assembly 10 to maintain the gate 40 in closed position; this member 43 is reciprocable in a horizontal path between locking and inoperative positions by a double-acting hydiaulic or pneumatic cylinder 44.

Due to the fact that at least the longer teeth on the wall 31 are staggered with reference to longer teeth on the wall 32, the comminuting unit 10 is capable of rapidly and predictably comminuting relatively large fragments of anode blocks 2 which abut against the teeth of one wall while the other wall 7 moves toward the one wall, or vice versa. Such comminuting action is further enhanced by the provision of elongated A cutting edges on some or all of the teeth which are provided on the walls 31, 32.

If desired, the comminuting assembly 10 can be located at one side of the separating station. The apparatus then comprises suitable means for transporting separated anode blocks 7 from the separating station into the crushing chamber 30. The

fragmentizing action of teeth on the walls 31, 32 is normally sufficient to comminute the blocks 2 into small particles which can be readily subjected to further comminuting action (if necessary) so as to obtain particulate material which is best suited for the production of fresh anode blocks. i The operation:

The cylinders 46, 14 and 11 are actuated to move the guide 1 frames 45, clamping or holding faces 13 and stripping or moving elements 19 apart prior to transport of an anode unit 1 into the space above the inlet 30a of the crushing chamber 30. The anode unit 1 is moved by its trolley 22 along the overhead rail 25 and comes to a halt when its anode rod 3 moves beyond the jaws 29 of the blocking device 27 to assume the position shown in FIG. 3. A stop (not shown) is provided on the guide rail 25 to arrest the trolley 22 when the corresponding anode rod 3 moves beyond the jaws 29. The rails 28 then insure that the spade 4 is located in a vertical plane at right angles to the axes of the piston rods 12 of the clamping cylinders 11. The cylinders 46 are thereupon actuated to move the guide frames 45 toward each other whereby the guide frames 45 move the carriages 47 and hence the supports 11a for the cylinders 11 and 14. The operative positions of one pair of clamping cylinders 11 with reference to an anode spade 4 are indicated in FIG. 4 by phantom lines; the corresponding clamping faces 13 then flank the adjoining prong 4a of the spade 4. The cylinders 11 are thereupon actuated to move the clamping faces 13 of their piston rods 12 into strong clamping engagement with the adjoining prongs 4a so as to make sure that the suspending device including the parts 3 and 4 is held against movement toward the crushing chamber 30. The operative positions of two clamping faces 13 are shown in FIG. 3 by phantom lines. Consequently, the stripping elements 19 and their scrapers 20 are held in operative positions and can respectively engage the anode block 2 and the surfaces of the spade 4 when the cylinders 14 are actuated to move the piston rods 13 downwardly. The scrapers 20 clean the surfaces of the spade 4 while they move downwardly with the stripping elements 19, and these stripping elements bear against the head of the anode block 2 and cause its separation from the prongs 4a of the spade 4 which is held by the faces 13 on the piston rods 12 of the clamping cylinders 11. The scrapers 20 are preferably designed in such a way that they remove all extraneous matter (mainly carbon) from the surfaces of the spade 4 and that they are also capable of removing from such surfaces all remnants of cast iron if such is used to anchor the prongs 4a in the bores of the block 2. When the block 2 is fully separated and descends into the crushing chamber 30 of the separating assembly 10, the cylinders 11, 14 and 46 are actuated to return the corresponding parts to the positions shown in FIG. 4 by solid lines. The suspending device including the rod 3 and spade 4 (which is clean) is thereupon removed by the corresponding trolley 22 and the apparatus is ready to treat the next anode unit 1. The blocks 2 of successively treated anode units 1 accumulate in the chamber 30 of the comminuting assembly 10. As stated above, the chamber 30 may also receive some parts which consist of cast iron, particularly such cast iron which is often used to anchor the prongs 4a of spades 4 in the heads of anode blocks 2. The accumulations in crushing chamber 30 are comminuted by repeatedly actuating the cylinder 33 which moves the wall 32 toward and away from the wall 31 until the material in the chamber 30 is a mass of comminuted granulae eventually containing some cast iron parts. The wall 32 can be moved back and forth once or more than once, and such movement or movements can be carried out whenever a freshly separated block 2 enters the chamber 30 or at longer intervals. Once the material in the chamber 30 is comminuted to a desired degree, the cylinder 39 is actuated to move the levelling ram 38 into the interior of the chamber in order to rake the broken up fragments and to bring about at least some further comminuting action. The gate 40 is unlocked in response to actuation of the cylinder 44 and is thereupon moved to open position by cylinder 42 so that the contents of the chamber 30 are dumped into a receptacle or onto a takeoff conveyor, not shown. Pieces of cast iron or other metallic particles can be separated from the material which is discharged from the chamber 30 by resorting to magnets or the like in a manner not forming part of the present invention.

The apparatus is susceptible of many additional modifications. For example, instead of transporting the anode units 1 horizontally along the overhead rail 25, the anode units can be moved from a lower level to a higher level so that their blocks 2 move into engagement with fixed stripping elements 19 or analogous separating devices. The conveyor for anode units is then preferably designed in such a way that it moves the anode units along a horizontal path well below the stripping elements into registry with the stripping station and thereupon upwardly so that the blocks 2 are separated automatically while the suspending devices continue to move upwardly. In other words, the conveyor for the anode units 1 can take over the function of cylinders 14. Furthermore, and as stated before, a single pair of clamping or holding cylinders 11 and a single pair of moving or stripping cylinders 14 will suffice if the anode units 1 are rather small. In such apparatus, the clamping cylinders can be omitted altogether and the stripping elements 19 can be fixedly mounted if the conveyor for the anode units 1 is designed to move the units sideways toward the stripping station and thereupon upwardly so that the fixed stripping elements engage the block 2 and prevent its movement with the ascending suspending device.

The mounting of supports 14a for the stripping cylinders 14 on the piston rods 12 of the clamping cylinders 11 brings about the advantage that the clamping and the corresponding stripping means can be moved simultaneously to optimum positions for treatment of successive anode units. However, it is also possible to mount and to move the stripping cylinders 14 independently of the clamping pistons 12. Furthermore, the teeth on the wall 31 or 32 can be omitted and the longer teeth may be provided with pointed tips. Also, longer teeth with horizontal cutting edges on the wall 31 or 32 may be provided in addition to longer teeth with vertical cutting edges and/or shorter teeth with horizontal and/or vertical cutting edges.

The operation of the apparatus can be programmed in such a way that the clamping, strip'ping, cleaning and comminuting devices are actuated in a predetermined sequence in response to automatic delivery of successive anode units 1. The apparatus can be used for recovery of carbon from remainders of anode units which are removed from electrolytic furnaces as well as for salvaging of carbon from a defective anode units, i.e., from such units which become defective during tamping of carbon, during anchoring of prongs 4a in the anode block, and/or during transport to the furnace.

It is further clear that the exact design and mode of operation of the conveyor system which delivers anode units to the clamping, stripping and comminuting means of the improved apparatus depends on the dimensions of the plant and/or on the dimensions of space which is available for installation of the conveyor system. Furthermore, the design of the conveyor system depends on the dimensions and mounting of other parts of the apparatus. As stated before, it is possible to utilize a conveyor system which delivers successive anode units in horizontal position so that the clamping device or devices can be dispensed with.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended l. A method of salvaging carbon from anode units of the type wherein an anode carbon block is connected to a suspending device which consists at least in part of metallic material, comprising the steps of mechanically clamping the suspending device; mechanically separating the anode block from the clamped suspending device; and subjecting the separated anode block to a comminuting operation.

2. A method as defined in claim 1, wherein said comminuting step comprises converting the anode block into a mass of granulae by subjecting it to a series of crushing actions.

3. A method as defined in claim 2, further comprising the step of levelling the granular material in the course of said comminutingo eration.

4. A metho as defined in claim 1, further comprising the step ofcleaning the exterior of the suspending device.

5. A method as defined in claim 4, wherein said cleaning step takes place simultaneously with mechanical separation of the anode block.

6. A method as defined in claim 5, wherein said cleaning step comprises scraping a portion of the clamped suspending device.

7. A method as defined in claim 1, further comprising the steps of separating the anode block from the suspending device of at least one additional anode unit and comminuting said last-mentioned anode block simultaneously with the firstmentioned anode block.

WEED STATES PATENT @FFMIE CERHMQATE QRREQTWN 3,658,261 Dated April 25, 193 2 Patent No.

Inventor(s) Gunter LiZHLOiIIBQl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet [73] the name of the first asaignee should read Lindemann Maschinenfabrik Gesellschait mit beschranktex" Hafcwng Signed and sealed this 19th day of December 1972,

(SEAL) Attest;

EDWARD MQFLETCHER WJRQ ROBERT GOTTSCHALK Commissioner of Patents Attesting Officer USCOMM-DC 60376-P69 N u.s. GOVERNMENT PRINTING OFFICE: 1969 o36s334,

FORM PO-1OSO (10-69) 

2. A method as defined in claim 1, wherein said comminuting step comprises converting the anode block into a mass of granulae by subjecting it to a series of crushing actions.
 3. A method as defined in claim 2, further comprising the step of levelling the granular material in the course of said comminuting operation.
 4. A method as defined in claim 1, further comprising the step of cleaning the exterior of the suspending device.
 5. A method as defined in claim 4, wherein said cleaning step takes place simultaneously with mechanical separation of the anode block.
 6. A method as defined in claim 5, wherein said cleaning step comprises scraping a portion of the clamped suspending device.
 7. A method as defined in claim 1, further comprising the steps of separating the anode block from the suspending device of at least one additional anode unit and comminuting said last-mentioned anode block simultaneously with the first-mentioned anode block. 